"This year, all of that will change radically and violently," wrote event organizer Bill Llewellin in a pre-convention mailing. "The winner will be the last critter standing (rolling, crawling) on the field of combat."

What he proposed was an event dubbed the Critter Crunch, in which competitors would face off on a folding table provided by the Executive Tower Inn. "Some potential entrants are discussing critters capable of significant mayhem," warned the mailer. "So don’t get too attached to your entry."

(Imagine a time when contestants actually needed to be warned that their robots might be damaged in combat!)

There had been public displays of robotic mayhem before: Survival Research Laboratories’ performance art pieces had featured automatons that spit fire and blew up. But this was an actual invitational sporting event.

Llewellin devised the parameters of the game, with input from fellow members of the Denver Mad Scientists Club. (Their standard uniform was a white lab coat and a hard hat.)

They codified 11 rules, a sort of Magna Carta of mechanical warfare. (No, scratch that, it was bigger than the Magna Carta: It was like a real-life version of Asimov’s Three Laws of Robotics.)

It was decreed that combatants must be neither heavier than 20 pounds nor bigger than 12 x 12 x 12 inches, though they “may deploy appendages beyond these dimensions.”

The Crunch attracted “five or 10” competitors, according to Llewellin. He himself fielded a fearsome forklift creature named Fluffy Bunny that upended numerous opponents before being outmaneuvered by a tiny Radio Shack radio-controlled car. (The lack of weight classes made for some chaotic David-and-Goliath matches.)

The ultimate winner was Mad Scientist member Pat Thompson’s Thing One, a 19-pound behemoth armed with a can of Silly String that it sprayed at foes — and the audience.

The Critter Crunch gave birth to an array of robot-fighting leagues worldwide, as well as a series of TV shows and videogames. It helped to popularize amateur automaton tinkering.

It also reminded us all that bots aren’t simply toys or industrial helpmates. They are dangerous and terrifying creatures that will someday conquer and enslave mankind.

Top Photo: Pat Thompson (right) and Bob Pfeiffer attempt to untangle Thing One's control cables after a match. Bottom Photo: A hole is left in Thing One by an air-powered harpoon from the machine Big Punch. The harpoon stuck in the aluminium, but failed to do any damage. (Courtesy Pat Thompson)